The present invention relates to a semiconductor device having such a structure that a plurality of packages packaged in the TAB method are stacked.
Very recently, a great demand for a higher density of electronic appliances is made. To satisfy such a demand, an arrangement as shown in FIG. 5 has been employed. FIG. 5 is a sectional view of an example of a conventional semiconductor device manufactured by the high density packaging A predetermined wiring pattern and electrodes 21a and 21b are formed on both sides of a circuit board 20. Each of wiring patterns formed on either side is electrically connected by a through hole (not shown) with each other. Packaged semiconductor chips 22a and 22b are mounted on both sides of the circuit boards 20. In accordance with such a conventional structure, a packaging density thereof becomes at least two times higher than that of the same plane area by mounting the packages on both sides of the circuit board 20.
In the conventional structure, however, since the packages are mounted on both sides of the circuit board in a plane form, only twice packaging density can be achieved. As a result, the more the number of the mounted chips increases, the higher the packaging area becomes. There is a problem that the higher density of the electronic appliances is impeded.